1. Field of the Invention
The present invention relates to a mobile rail grinding machine for grinding irregularities off a surface area of a rail head of track rails, the rail head having side faces and rounded edges connecting the side faces to the surface area. The machine comprises a machine frame extending in a longitudinal direction, undercarriages supporting the machine frame on the track rails for movement in an operating direction, a mounting frame supported on the track rails by flanged wheels, and a drive vertically adjustably connecting the mounting frame to the machine frame. At least one rail head grinding unit on the mounting frame comprises an abrasive belt having opposite ends, a storage spool holding one of the belt ends and a collecting spool holding the opposite belt end whereby the abrasive belt may be reeled off the storage spool and onto the collecting spool, and a pressure element arranged to press the abrasive belt against the surface area of the rail head off which the irregularities are to be ground.
2. Description of the Prior Art
A mobile rail grinding machine of this general type has been disclosed in Austrian patent No. 221,131, in which a respective grinding unit is associated with each track rail to grind irregularities off the surface areas of the rail heads of the track rails. The mounting frame for the grinding units is linked to the machine frame by tie rods, and flanged wheels support the mounting frame on the track rails. A drive is connected to the machine frame for lifting the mounting frame off the track rails. Independently of this vertical adjustment of the mounting frame, the grinding units may be vertically adjusted on the mounting frame along guides and may be pressed down by drives mounted on the machine frame so that a pressure shoe may press the abrasive band against the surface area of the rail head. The spools, which hold the opposite ends of the abrasive band, have ratchet wheels and pawls for preventing their rotation and fixing the abrasive band in position. During operation, the machine is advanced along the track while the abrasive bands of the grinding units are pressed against the surface areas of the rail heads. After a section of the abrasive band is worn out, the spools are periodically rotated while the grinding units are lifted off the rails to place a succeeding section of the abrasive band into an operating position.
U.S. Pat. No. 4,249,346 also describes a mobile rail grinding machine. Its grinding units are mounted on carrier frames having flanged wheels running on the track rails. Tie rods and a lever system link the grinding units to a crank drive mounted on the machine frame so that a reciprocating motion is imparted to the units in a direction opposite to that of the advancement of the machine along the track.
The rail grinding machine of U.S. Pat. No. 4,896,460 uses an endless abrasive band trained about vertically spaced, driven guide rollers rotating about axes extending transversely to the longitudinal direction, and the band is pressed against the surface area of the rail head to be ground. The carrier frame for the abrasive band is vertically adjustable to bring the band into its operating position.
German patent No. 3,840,006 discloses a rail grinding device comprising an endless abrasive band displaced transversely to the longitudinal direction of the rail over the surface of the rail head. The abrasive band is trained over guide rollers which may be lowered at both sides of the rail head below the surface whereby the abrasive band partially surrounds the rail head in the operative position.